JP2014169446A - Propylene resin composition for stretched sheet, and stretched sheet and thermo-formed body including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a propylene resin composition for stretched sheets, excellent in rigidity, heat-resistant rigidity, transparency, uniform stretchability and thermo-formability, and a stretched sheet and thermo-formed body including the resin composition.SOLUTION: The propylene resin composition for stretched sheets is obtained by including 10-90 wt.% of a high melting point propylene resin (A') having 156-170°C of a melting point measured by a DSC and 10-90 wt.% of at least one or more kinds of low melting point propylene resins (A'') having 70-155°C of a melting point measured by the DSC (where, the total amount of A' and A'' is 100 wt.%) and satisfies following requirements [1]-[4]. [1] A melt flow rate (230°C, 2.16 kg loads) is 0.5-10.0 g/10 min. [2] A melting point measured by the DSC is 150-170°C. [3] In the propylene resin composition for stretched sheets (A), a α-olefin comonomer content is 1-11 mol%. [4] A nucleating component is included.

Description

  The present invention relates to a propylene-based resin composition for a stretched sheet, and a stretched sheet and a thermoformed article containing the resin composition.

  Highly transparent sheets are widely used as packaging materials for food, medical instruments, pharmaceuticals, electronic parts, stationery, miscellaneous goods and the like. As materials, there are many biaxially oriented polystyrene (OPS) sheets, polyvinyl chloride (PVC) sheets, or amorphous polyethylene terephthalate (A-PET) sheets due to transparency, rigidity, and secondary formability (thermoformability). .

  In recent years, substitution to a polypropylene sheet has been promoted from the viewpoints of environmental protection, heat resistance rigidity, oil resistance, low specific gravity and the like.

  Since polypropylene is crystalline, it becomes a translucent sheet as it is. Therefore, as a general method for improving transparency and rigidity, a method of adding a nucleating agent is known (for example, described in JP-A No. 2002-284944). However, since the rigidity (room temperature) and transparency are insufficient even in the above method, the substitution to the polypropylene sheet is limited to some applications.

  By the way, it is known that polypropylene has improved physical properties such as rigidity and transparency by stretching.

  The stretching ratio of a biaxially stretched polypropylene film, which is well known as BOPP, is usually performed at a high ratio of about vertical × horizontal = 5 × 10 times. In order to obtain the sheet thickness (0.1 to 1 mm) as an object of the present invention by such high-stretch stretching, it is necessary to set the sheet (raw fabric) thickness before stretching to 5 to 50 mm (BOPP is Usually, 1 to 3 mm), when it becomes such a thick original, it is difficult to form the original, and it cannot be stretched with the existing equipment. When the original fabric has a normal thickness and is stretched at a low magnification, stretching unevenness (thickness unevenness) due to undrawn (necking) is likely to occur, and it is difficult to obtain a target sheet thickness.

  In the case of uniaxial stretching, there is less stretching unevenness than the above-described method even as low-magnification stretching, and it is relatively easy to obtain the desired sheet thickness, but it is necessary to suppress the stretching ratio to 3 times or less because of thermoformability. Therefore, sheet physical properties such as rigidity and transparency are insufficient (for example, JP-A-53-94371 and JP-A-53-128673). Further, although a method of uniaxially stretching by combining a special raw material quenching method is also known (for example, Japanese Patent Publication No. 63-16256, Japanese Patent Publication No. 63-62377), the sheet physical properties are somewhat improved but sufficient. In addition, it is not preferable because the equipment cost (manufacturing cost) becomes expensive.

JP 2002-284944 A JP-A-53-94371 JP-A-53-128673 Japanese Examined Patent Publication No. 63-16256 Japanese Examined Patent Publication No. 63-62377

  The present invention is intended to solve the problems associated with the prior art as described above, and is not limited by stretching methods such as uniaxial stretching, biaxial stretching, raw sheet cooling, and stretching ratio, and is excellent. Another object of the present invention is to provide a propylene-based resin composition for a stretched sheet having high rigidity, heat-resistant rigidity, transparency, uniform stretchability, and thermoformability, and a stretched sheet and a thermoformed body containing the resin composition.

  As a result of diligent research to solve the above-mentioned problems, the inventors of the present invention can stretch a resin composition having a wide composition distribution combining propylene resins having a melting point in a specific range without being restricted by a stretching method. Furthermore, the stretched sheet containing the resin composition was found to have a very good balance of rigidity, heat-resistant rigidity, transparency, uniform stretchability, and thermoformability, and the present invention was completed.

  That is, this invention is specified by the matter described below.

(1) 10 to 90% by weight of a high melting point propylene resin (A ′) having a melting point measured by DSC of 156 to 170 ° C. and at least one low melting point propylene having a melting point of 70 to 155 ° C. measured by DSC -Based resin (A ″) 10 to 90% by weight (however, the sum of A ′ and A ″ is 100% by weight), and for stretched sheets that simultaneously satisfy the following requirements [1] to [4] Propylene resin composition (A).
[1] The MFR (230 ° C., 2.16 kg load) is 0.5 to 10.0 g / 10 min.
[2] The melting point measured by DSC is 150 to 170 ° C.
[3] The α-olefin comonomer content is 1 to 11 mol% in the propylene-based resin composition (A) for stretched sheets.
[4] Includes nucleating components.

  (2) The α-olefin comonomer content of the high melting point propylene-based resin (A ′) is 0 to 1.5 mol%, and the α-olefin comonomer content of the low melting point propylene resin (A ″) is 1.6 to 24 mol%. The propylene-based resin composition (A) for stretched sheet according to (1).

  (3) A monolayer sheet (B1) obtained by stretching the propylene-based resin composition (A) for stretched sheet according to (1) or (2) in at least a uniaxial direction.

(4) A multilayer sheet (B2) using the propylene-based resin composition (A) for stretched sheet according to (1) or (2) as at least either the uppermost layer or the lowermost layer, and the multilayer sheet Are at least uniaxially stretched, and the melting point (Tm1) of the uppermost layer and the melting point (Tm2) of the lowermost layer of the multilayer sheet are
1 ≦ Tm2−Tm1 ≦ 100 (° C.)
Multi-layer sheet (B2) that satisfies the above relationship.

(5) A multilayer sheet (B2 ′) in which the propylene-based resin composition (A) for stretched sheet according to (1) or (2) is used for both the uppermost layer and the lowermost layer, and the multilayer sheet (B2 ') The α-olefin comonomer content (C1) of the resin composition constituting the uppermost layer and the α-olefin comonomer content (C2) of the resin composition constituting the lowermost layer,
C1> C2
Multi-layer sheet (B2 ') that satisfies the above relationship.

  (6) A thermoformed article obtained by thermoforming the single-layer sheet (B1) according to (3).

  (7) A thermoformed article obtained by thermoforming the multilayer sheet (B2) according to (4) or the multilayer sheet (B2 ′) according to (5).

  (8) A thermoformed article used as a material for wrapping contents of food, medical instruments, pharmaceuticals, electronic parts, stationery, miscellaneous goods, etc., wherein the uppermost layer of the multilayer sheet (B2) or (B2 ′) The thermoformed article according to (7), which is obtained by thermoforming the contents so as to be on the outer surface side.

  The monolayer and multilayer stretched sheets containing the propylene-based resin composition (A) for stretched sheets of the present invention have a very good balance of rigidity, heat resistance rigidity, transparency, uniform stretchability, and thermoformability. And the thermoforming body obtained from this single layer and multilayer stretched sheet has the characteristics that rigidity, heat-resistant rigidity, transparency, oil resistance, etc. are high, and it is low specific gravity. Moreover, the thermoformed body obtained from this multilayer stretched sheet has excellent shape stability because it has little post-molding shrinkage and little deformation. For this reason, the single-layer and multilayer stretched sheets containing the propylene-based resin composition (A) for stretched sheets of the present invention can be widely used as packaging materials for foods, medical instruments, pharmaceuticals, electronic parts, stationery, miscellaneous goods and the like. .

  The propylene resin composition (A) for stretched sheets of the present invention comprises a high melting point propylene resin (A ′) and at least one low melting point propylene resin (A ″).

High melting point propylene resin (A ')
The high melting point propylene-based resin (A ′) has a melting point (Tm) measured by DSC of 156 to 170 ° C., preferably 160 to 170 ° C., more preferably 163 to 170 ° C. When Tm is within this range, the stretched sheet containing the propylene-based resin composition (A) of the present invention is excellent in rigidity and heat resistance rigidity.

  The high melting point propylene-based resin (A ′) is a polymer containing propylene as a constituent unit, and is a propylene homopolymer or propylene and ethylene or an α-olefin having 4 to 20 carbon atoms (α-olefin comonomer). ) And a random copolymer. Here, examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1 -Tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like. Among these, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable. The content of the α-olefin comonomer is 0 to 1.5 mol%, preferably 0 to 1.2 mol%, and more preferably 0 to 0.6 mol% in the high melting point propylene resin (A ′).

  The preferred embodiment of the high melting point propylene resin (A ′) is a melt flow rate (MFR) (230 ° C., 2.16 kg load) of 0.3 to 15.0 g / 10 min, more preferably 0.6 to 9.0 g / 10 min. It is in. When the MFR is within this range, the extrudability of the raw material is excellent.

Further, a preferred embodiment of the high melting point propylene-based resin (A ′) has a stereoregularity index [M ₅ ] value of 0.960 determined by the following formula (Eq-1) from the absorption intensity of Pmmmm and Pw in ¹³ C-NMR spectrum. ˜0.990, more preferably in the range of 0.970 to 0.990. When the stereoregularity index [M ₅ ] is in this range, the stretched sheet has excellent rigidity and heat resistance rigidity.

(In the formula, [Pmmmm] indicates the absorption intensity derived from the methyl group of the third unit at the site where 5 units of the propylene unit are isotactically bonded, and [Pw] is derived from the methyl group of the propylene unit. Indicates the absorption intensity.)
Examples of the method for producing such a high melting point propylene-based resin (A ′) include methods described in JP-A-2-84404, JP-A-2-229807, JP-A-3-7703, and the like. Can be used.

Low melting point propylene resin (A '')
The low melting point propylene-based resin (A ″) has a Tm in the range of 70 to 155 ° C., preferably 70 to 150 ° C., and more preferably 78 to 148 ° C. When Tm is within this range, the stretched sheet containing the propylene-based resin composition (A) of the present invention is excellent in transparency, uniform stretchability, and thermoformability.

  Low melting point propylene-based resin (A ″) is a polymer containing propylene as a constituent unit, and is a random copolymer of propylene and ethylene or an α-olefin (α-olefin comonomer) having 4 to 20 carbon atoms. It is a coalescence. Here, examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1 -Tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like. Among these, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable. The content of the α-olefin comonomer is 1.6 to 24 mol%, preferably 3.0 to 24 mol%, more preferably 3.7 to 24 mol% in the low melting point propylene resin (A ″).

  In a preferred embodiment of the low-melting-point propylene-based resin (A ″), the MFR (230 ° C., 2.16 kg load) is in the range of 0.3 to 15.0 g / 10 min, more preferably 0.6 to 9.0 g / 10 min. When the MFR is within this range, the extrudability of the raw material is excellent.

  Such a low melting point propylene resin (A ″) can be produced by the above high melting point propylene resin (A ′) as long as Tm is 130 ° C. or higher, but Tm is 130 ° C. If it is less than 1, the amount of atactic polypropylene produced increases, so it cannot be used. On the other hand, the method using a metallocene catalyst is particularly preferable as a method for producing a low melting point propylene resin (A ″) because the amount of atactic polypropylene produced can be suppressed. For example, WO01 / 027124, JP2002-2002 The methods described in JP-A-275282, JP-A-2002-275330, JP-A-2002-275331, JP-A-2002-275332, and the like can be used.

Propylene resin composition for stretched sheet (A)
The propylene resin composition (A) for stretched sheets of the present invention is a resin composition in which a high melting point propylene resin (A ′) and at least one or more low melting point propylene resins (A ″) are combined. The composition ratio of the resin composition (A) is such that the high-melting-point propylene-based resin (A ′) is 10 to 90% by weight, preferably 20 to 80% by weight, in the resin composition (A). The low melting point propylene-based resin (A ″) is 10 to 90% by weight, preferably 20 to 80% by weight (as a total amount of the resin (A ″) in the case of two or more types).

  The propylene-based resin composition (A) for stretched sheets of the present invention has an MFR (230 ° C., 2.16 kg load) of 0.5 to 10.0 g / 10 min, preferably 1.0 to 5.0 g / 10 min, and a Tm of 150 -170 ° C, preferably 155-170 ° C, more preferably 158-170 ° C, and the α-olefin comonomer content in the resin composition (A) is 1.0-11 mol%, preferably 1.5-8 mol% And includes a nucleating component.

  The propylene-based resin composition (A) for stretched sheets of the present invention can be produced by multistage polymerization. For example, in a polymerization tank of two or more stages connected in series, a high melting point propylene resin (A ′) can be produced in the former stage and a low melting point propylene resin (A ″) can be produced continuously in the latter stage. Is possible.

  In addition to the above, separately manufactured high melting point propylene resin (A ′) and low melting point propylene resin (A ″) using a single screw extruder, multi screw extruder, kneader, or Banbury mixer It is possible to obtain a propylene resin composition (A) by melting and kneading, and in addition, the resin can be directly used in a sheet molding machine.

The nucleation components contained in the nucleating stretched sheet for the propylene resin composition of the components present invention (A), a known nucleating agents can be used without limitation. For example, sorbitol compounds, phosphate compounds, aliphatic dicarboxylic acids having 4 to 12 carbon atoms and metal salts thereof, aromatic carboxylic acids and metal salts thereof, rosin acid metal salt compounds, and magnesium silicate (talc) Etc. In addition, a polypropylene (polymer nucleating agent) obtained by prepolymerizing a reactive monomer serving as a nucleating component on a polypropylene polymerization catalyst and then polymerizing propylene is also included in the nucleating component. Among these nucleating components, the above polymer nucleating agent is preferable because of its high compatibility and high nucleating effect and very little contamination to the sheet molding machine and thermoforming machine.

  Examples of reactive monomers used in the prepolymerization of the polymer nucleating agent include 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4, 4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, allylnaphthalene, allylnorbornane, styrene, dimethylstyrenes, vinylnaphthalenes, Examples include allyltoluenes, allylbenzene, vinylcyclohexane, vinylcyclopentane, vinylcycloheptane, and allyltrialkylsilanes.

  As the method for producing the polymer nucleating agent, methods described in JP-A-4-202505, JP-A-4-202506, JP-A-4-202510, etc. can be used.

  These nucleating components are 0.001 to 0.5 parts by weight, preferably 0.0018 to 0.3 parts by weight, per 100 parts by weight of the propylene-based resin composition (A) for stretched sheets.

Additives When forming a stretched sheet from the propylene-based resin composition (A) for stretched sheet of the present invention as a raw material, an antioxidant, a light-resistant stabilizer, an ultraviolet absorber, a metal are used without departing from the object of the present invention. Additives such as soap, hydrochloric acid absorbent, lubricant, antistatic agent, antifogging agent, and antiblocking agent may be added.

  The addition amount of these additives varies depending on the type, but may be in a range that does not impair the object of the present invention, and is usually 3 parts by weight with respect to 100 parts by weight of the propylene-based resin composition for stretched sheet (A). It is as follows.

Stretched sheet and thermoformed body A sheet containing the propylene-based resin composition (A) for stretched sheet of the present invention and stretched at least in a uniaxial direction is rigid, heat-resistant rigidity, transparency, uniform stretchability, and thermoformability. The balance is very good.

  The stretched sheet of the present invention is obtained by a known production method. For example, the stretched sheet propylene-based resin composition (A) is supplied to an extruder (in the case of a multilayer, a plurality of extruders are used), and a resin is obtained. Adjusting the temperature to 190-280 ° C, extruding from a T-die attached to the tip of the extruder (in the case of multiple layers, just before the T-die or after joining in the T-die), cooling roll adjusted to a temperature of 20-80 ° C The take-up raw fabric is formed by. Furthermore, it is reheated with a preheating roll adjusted to a temperature of 130 to 160 ° C., roll-stretched at a draw ratio of 2 to 5 times in the longitudinal direction, and 0 to Can be obtained by winding while relaxing 10%.

  In addition, the stretching method is not limited, and in addition to the above-described longitudinal uniaxial stretching, it may be lateral uniaxial stretching that stretches in the transverse direction with a tenter, and successive stretching in the transverse direction with the tenter after the longitudinal uniaxial stretching. Biaxial stretching or simultaneous biaxial stretching in which only a tenter is used for stretching in the vertical and horizontal directions may be used.

  The preferred draw ratio when producing the stretched sheet of the present invention is 2 to 6 times, more preferably 3 to 5 times in the case of uniaxial stretching, and 2 to 6 times in the longitudinal / lateral directions in the case of biaxial stretching, and more. The range is preferably 3 to 5 times.

  The stretched sheet of the present invention is a single layer sheet (B1) made of the propylene-based resin composition (A) for stretched sheets or a multilayer sheet (B2) having two or more layers containing the resin composition (A).

  Usually, a polypropylene stretched sheet is characterized by shrinking because a molecular chain that has been tensioned by stretching is relaxed by heat. Since the glass transition temperature (Tg) of polypropylene is 0 ° C. or less, it gradually shrinks even at room temperature (post-shrinking). Thermoformed bodies that have been subjected to secondary processing by hot forming such as hot plate forming, vacuum pressure forming, etc. after polypropylene stretched sheet may shrink and deform after storage in summer (high temperature) or long-term storage (containers etc.) In the case of a shape having a square, the edge of the thermoformed body is likely to be deformed to warp to the outer surface side relative to the original state. Since the same applies to the thermoformed body comprising the single-layer sheet (B1) of the present invention, the shape and storage method of the thermoformed body are subject to some restrictions.

  On the other hand, the thermoformed body made of the multilayer sheet (B2) of the present invention is extremely small in the deformation, so that the restrictions on the shape, storage method, etc. can be eliminated or alleviated.

The multilayer sheet (B2) of the present invention uses the propylene-based resin composition (A) for stretched sheets of the present invention at least in either the uppermost layer or the lowermost layer, and the uppermost layer has a lower melting point polypropylene than the lowermost layer. The propylene-based resin composition (A) for a stretched sheet is preferably used. At this time, the melting point difference (ΔTm) of the uppermost lower layer (both outermost layers) is 1 to 100 ° C., preferably 3 to 30 ° C., more preferably 3 to 15 ° C. That is, the melting point (Tm1) of the uppermost layer and the melting point (Tm2) of the lowermost layer of the multilayer sheet satisfy the relationship (I), preferably satisfy the relationship (II), and more preferably satisfy the relationship (III). It is important to design the layer structure.
(I) 1 ≦ Tm2−Tm1 ≦ 100 (° C.)
(II) 3 ≦ Tm2−Tm1 ≦ 30 (° C.)
(III) 3 ≦ Tm2−Tm1 ≦ 15 (° C.)

  The multilayer sheet (B2 ′) of the present invention uses the propylene-based resin composition for stretched sheets (A) of the present invention for both the uppermost layer and the lowermost layer, and the α-olefin of the resin composition constituting the uppermost layer. It is important that the comonomer content (C1) and the α-olefin comonomer content (C2) of the resin composition constituting the lowermost layer satisfy the relationship of C1> C2.

  Further, when the multilayer sheet is thermoformed, the sheet is oriented so that the uppermost layer (low Tm) is formed on the outer surface side of the thermoformed body and the lowermost layer (high Tm) is formed on the inner surface side. It is possible to suppress deformation due to contraction.

  That is, when thermoforming the multilayer sheet of the present invention having the above-described configuration, the uppermost layer (low Tm side) of the multilayer sheet (B2) or (B2 ′) is the outer surface side with respect to the contents, and the lowermost layer According to another expression, the uppermost layer (low Tm side) of the multilayer sheet (B2) or (B2 ′) is the shape of the thermoformed body so that the (high Tm side) is the inner surface side with respect to the contents. It is possible to suppress deformation due to post-shrinkage by molding the sheet so that the lowermost layer (high Tm side) is on the inside of the concave surface outside the convex surface.

  In addition, when thermoforming the multilayer sheet (B2 ′) of the present invention having the above configuration, the uppermost layer (C1 side) of the multilayer sheet (B2 ′) is the outer surface side with respect to the contents, and the lowermost layer ( According to another expression, the uppermost layer (C1 side) of the multilayer sheet (B2 ') is on the outer side of the convex surface of the thermoformed body, It is also possible to suppress deformation due to post-shrinkage by molding the sheets so that the (C2 side) is inside the concave surface.

  Usually, drawing of polypropylene is performed in a temperature range of crystallization temperature (Tc) or more and Tm or less. The amount of post-shrinkage of the stretched sheet depends on the stretching temperature. The lower the stretching temperature (near Tc), the larger the post-shrink amount, and the higher the stretching temperature (near Tm), the smaller the post-shrink amount. Indicates. Therefore, the thermoformed body comprising the multilayer sheet (B2) has the uppermost layer (low Tm) on the outer surface side of the thermoformed body and the lowermost layer (high Tm) on the inner surface side. Since the film is stretched in the vicinity of Tm rather than the side, the amount of post-shrinkage on the outer surface side of the thermoformed body is smaller than that on the inner surface side, so that deformation is extremely small. In addition, by adjusting the melting point difference (ΔTm), the layer thickness ratio, the stretching temperature, and the like of the multilayer sheet, the amount of post-shrinkage on the inner and outer surfaces can be arbitrarily controlled, so that it is possible to deal with various shapes. .

  The multilayer sheet (B2) of the present invention can be given further added value by combining another resin with the intermediate layer without departing from the object of the present invention. For example, by using an ethylene / vinyl alcohol copolymer in the intermediate layer, oxygen and carbon dioxide barrier properties are improved, and if a polypropylene resin composition containing a hydrogenated petroleum resin is used in the intermediate layer, water vapor barrier properties are improved. Etc. In addition, other resins used for the intermediate layer include, for example, polyvinyl alcohol resins, polyvinylidene chloride resins, polyacrylonitrile resins, polyamide-based resins such as metaxylenediamine 6 and nylon 6, polyethylene terephthalate, polybutylene terephthalate, and the like. A polyester-type resin is mentioned.

  Further, the thermoformed product obtained from the stretched sheet of the present invention has high rigidity, heat resistance rigidity, transparency, oil resistance and the like, and has a low specific gravity. Therefore, foods, medical instruments, pharmaceuticals, electronic parts, stationery, miscellaneous goods It can be used widely as a packaging material.

〔Example〕
EXAMPLES Next, although this invention is demonstrated in detail based on an Example, this invention is not limited to those Examples.
The measuring method of the physical property in an Example is as follows.

1) Melt flow rate (MFR [g / 10min])
According to ASTM D-1238, the measurement was performed at a temperature of 230 ° C. and a load of 2.16 kg. The cylinder was directly charged into the cylinder and melted without introducing nitrogen.

2) Melting point (Tm [° C])
Appears when DSC raises the temperature from 30 ° C to 230 ° C at 10 ° C / min, holds at 230 ° C for 10 minutes, cools to 30 ° C at 10 ° C / min, and then raises again at 10 ° C / min The endothermic peak temperature was taken as the melting point.

3) Isotactic pentad fraction (mmmm: [M ₅ ])
^It was determined by the above formula (Eq-1) from the absorption intensity of Pmmmm and Pw in the ¹³ C-NMR spectrum. However, peak assignment was performed according to Polymer, 1993, Vol34, No14, 3129-3131.

4) Uniform stretchability (thickness unevenness [-])
The thickness of the stretched sheet was measured at a total of 30 locations at predetermined intervals, and the value obtained by dividing the standard deviation by the average thickness was used as an index of uniform stretchability (the smaller the value, the better the uniform stretchability).

5) Tensile modulus (MPa)
A test piece of ASTM D-638 type 4 was punched from the sheet, and the distance between chucks was 46 mm, the speed was 50 mm / min, the temperature was 23 ° C. or 110 ° C., and the initial slope of the stress-strain curve when pulled was obtained.

6) Degree (HAZE [%])
Measured with a Nippon Denshoku Industries TURBIDIMETER using an integrating sphere 150φ in accordance with JIS K7361.

7) Heat shrinkage (SH [%])
A test piece 10 mm wide and 100 mm long (L0) was punched from the sheet, heated in an air oven at 130 ° C. for 15 minutes, the length after heating (L1) was measured, and calculated from the following formula (Eq-2) .

8) Thermoformability (molding score [point])
Using a container model mold (dimension: □ 90mm, depth: 20mm) with a hot plate molding machine, thermoforming under specified molding conditions, and the shape of the resulting thermoformed body (model mold moldability) Was visually evaluated on a 5-point scale (the larger the value, the better the thermoformability, and a rating of 3 or higher is preferred).

9) Deformation amount of thermoformed product (warp deformation amount [mm])
The thermoformed product was aged in an air oven at 50 ° C. for 1 day, and the amount of warping of the edge of the thermoformed product was measured.

10) Specific gravity
Based on JIS7112, it was measured by an underwater substitution method.

[Example 1]
After pre-polymerizing 3-methyl-1-butene (3MB-1) as a nucleating component, propylene-based high-melting resin with Tm = 167 ° C, MFR = 2g / 10min, mmmm = 0.972 (A Resin composition combining 75% by weight of '-1), low melting point propylene resin (A''-1) of Tm = 135 ° C and MFR = 2g / 10min copolymerized with 6% by weight of propylene and ethylene Tetrakis [methylene-3 (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane (IRGANOX1010, trade name, manufactured by Ciba Specialty Chemicals) as an antioxidant for 100 parts by weight of the product 0.1 parts by weight and 0.1 parts by weight of tris (2,4-di-t-butylphenol) phosphate (IRGAFOS168, manufactured by Ciba Specialty Chemicals, Inc.), 0.1 parts by weight of calcium stearate (manufactured by NOF Corporation) as a neutralizing agent Partly blended and melt kneaded at a resin temperature of 230 ° C using a single screw extruder. It was granulated to toilet-shaped. At this time, the proportion of the 3MB-1 polymer which is a nucleating component is 0.027% by weight in the resin composition. The physical properties of the obtained resin composition (pellet) are shown in Tables 1 and 2.

  The above pellets are supplied to a longitudinally uniaxially stretched sheet molding machine, extruded from a T-die at a resin temperature of 250 ° C, formed into a 1.2mm-thick original fabric while being taken up by a cooling roll at a temperature of 30 ° C, and re-used by a preheating roll at a temperature of 150 ° C. After heating, roll stretching was performed at a stretching ratio of 4 and annealing was performed at a temperature of 110 ° C. to obtain a longitudinally uniaxially stretched sheet having a thickness of 0.3 mm. The physical properties of the obtained sheet are shown in Tables 1 and 2.

  The stretched sheet is set in a hot plate molding machine using the container model mold, set to a compressed air pressure of 0.64 MPa, a vacuum degree of 0.09 MPa, a sheet heating time of 3 s, and a molding time of 3 s, and a hot plate temperature of 100 to 160 ° C. Tables 1 and 2 show the best molding scores without white turbidity among the thermoformed products obtained.

[Example 2]
50% by weight of the high melting point propylene resin (A′-1) used in Example 1 and 50% by weight of the low melting point propylene resin (A ″ -1) used in Example 1 The ratio of 3MB-1 polymer was the same as in Example 1 except that 0.018% by weight in the resin composition was used, and the results are shown in Table 1. [Example 3]
After prepolymerizing 3-methyl-1-butene as a nucleating component, propylene homopolymerized with a high melting point propylene resin (A'-2) with Tm = 166 ° C., MFR = 11 g / 10 min, mmmm = 0.972 50% by weight, a resin composition obtained by combining 50% by weight of the low melting point propylene resin (A ″ -1) used in Example 1 (the proportion of 3MB-1 polymer is 0.017% by weight in the resin composition) The procedure was the same as in Example 1 except that was used, and the results are shown in Table 1.

[Example 4]
Low melting point propylene resin (Am) of Tm = 135 ° C. and MFR = 10 g / 10 min obtained by copolymerizing 50% by weight of the high melting point propylene resin (A′-2) used in Example 3 and 6 mol% of propylene and ethylene (A '' -2) was used in the same manner as in Example 1 except that a resin composition in which 50% by weight was combined (the proportion of the 3MB-1 polymer was 0.017% by weight in the resin composition). Shown in 1.

[Example 5]
Low melting point propylene resin having a Tm = 140 ° C. and MFR = 0.5 g / 10 min obtained by copolymerizing 50% by weight of the high melting point propylene resin (A′-1) used in Example 1 and propylene and 5.4 mol% of ethylene. The result was the same as in Example 1 except that a resin composition in which 50% by weight of (A ''-3) was combined (the proportion of the 3MB-1 polymer was 0.018% by weight in the resin composition) was obtained. The results are shown in Table 1.

[Example 6]
Propylene homopolymer Tm = 165 ° C., MFR = 0.5 g / 10 min, mmmm = 0.79% high melting point propylene resin (A′-3) 40% by weight, low melting point propylene resin used in Example 5 ( 50% by weight of A ''-3), and a resin composition in which 10% by weight of the propylene-based resin (A'-1) used in Example 1 as a nucleating component (the proportion of the 3MB-1 polymer is Example 1 was performed except that 0.0036 wt%) was used in the resin composition, and the results are shown in Table 1.

[Example 7]
Low melting point propylene resin (Tm = 138 ° C., MFR = 1.3 g / 10 min) obtained by copolymerizing 25% by weight of the high melting point propylene resin (A′-1) used in Example 1 and 4 mol% of propylene and ethylene (MFR = 1.3 g / 10 min) Ultra low melting point propylene resin (A ''-5) with Tm = 78 ℃ and MFR = 7g / 10min copolymerized with 50% by weight of A ''-4) and 23.5mol% of propylene and 1-butene As a nucleating agent, bis [2,4,8,10-tetra-t-butyl-6-hydroxy-12H-dibenzo [d, g] [100 parts by weight of a resin composition comprising 25% by weight] 1,3,2] dioxaphosphocin-6-oxide] The same as Example 1 except that a resin composition in which 0.13 parts by weight of aluminum hydroxide salt (NA-21, ADEKA, trademark) was combined was used. The mixture was melt-kneaded and granulated into pellets (the proportion of the 3MB-1 polymer was 0.009% by weight in the resin composition). Further, a stretched sheet was formed in the same manner as in Example 1 except that the pellets were supplied to a sheet forming machine and the preheating roll temperature was changed to 130 ° C. Table 1 shows the results.

[Comparative Example 1]
The low melting point propylene resin (A ″ -1) was removed from the resin composition used in Example 1, and only the high melting point propylene resin (A′-1) was 100% by weight (the proportion of the 3MB-1 polymer was The procedure was the same as Example 1 except that 0.036 wt% was added to the resin. The results are shown in Table 1.

[Comparative Example 2]
The nucleating component (A'-1) was removed from the resin composition used in Example 6, the high melting point propylene resin (A'-3) was 50% by weight, and the low melting point propylene resin (A ''-3) ) Was performed in the same manner as in Example 1 except that the resin composition was combined by 50% by weight. The results are shown in Table 1.

[Comparative Example 3]
The high melting point propylene resin (A'-1) and the ultra low melting point propylene resin (A ''-5) were removed from the resin composition used in Example 7, and the low melting point propylene resin (A ''-4) ) Was made in the same manner as in Example 7 except that the resin composition was combined with 100% by weight and only 0.13 part by weight of the nucleating agent (NA-21). The results are shown in Table 1.

[Comparative Example 4]
50% by weight of the propylene resin (A′-1) used in Example 1 and 50% by weight of the ultra-low melting point propylene resin (A ″ -5) used in Example 7 (3 MB) The ratio of the -1 polymer was the same as in Example 7 except that 0.018% by weight in the resin composition was used, and the results are shown in Table 1.

[Example 8]
The pellets obtained in Example 1 were sequentially fed to a biaxially stretched sheet molding machine, extruded from a T-die at a resin temperature of 250 ° C., and formed into a 1.8 mm thick raw material while being drawn with a cooling roll at a temperature of 30 ° C. Re-heated with a preheated roll at 150 ° C, roll-stretched at a stretch ratio of 3 times, then supplied to the tenter, stretched laterally at a stretch temperature of 155 ° C and stretch ratio of 3 times, and relaxed by 5% at 160 ° C Then, annealing was performed to obtain a sequentially biaxially stretched sheet having a thickness of 0.2 mm. The physical properties of the obtained sheet are shown in Table 2.

[Example 9]
In Example 8, a raw material having a thickness of 3.0 mm was formed, and the same operation as in Example 8 was performed except that the transverse stretching was changed to 5 times. The results are shown in Table 2.

[Example 10]
Cut the raw material with a thickness of 1.8 mm obtained in Example 8 into a size of □ 85 mm, and at the same time with a desktop type biaxial stretching machine at a stretching temperature of 155 ° C. and a stretching ratio of length × width = 3 × 3 times After biaxial stretching, annealing was performed at a temperature of 160 ° C. while relaxing 5% of the width to obtain a simultaneous biaxially stretched sheet having a thickness of 0.2 mm. The physical properties of the obtained sheet are shown in Table 2.

[Comparative Example 5]
The pellets obtained in Example 1 were supplied to a sheet molding machine, extruded from a T die at a resin temperature of 250 ° C., and an unstretched sheet having a thickness of 0.3 mm was obtained while being taken up by a cooling roll at a temperature of 30 ° C. The physical properties of the obtained sheet are shown in Table 2.

[Example 11]
Using a multilayer sheet molding machine with two extruders, the upper layer (low melting point layer) is 20% by weight of the high melting point propylene resin (A'-1) used in Example 1, propylene and ethylene 6 mol% A resin composition comprising 80% by weight of a low melting point propylene-based resin (A ''-6) with a Tm = 139 ° C and MFR = 3g / 10min blended with 0.03 parts by weight of talc (granulation is In the lower layer, 50% by weight of the above high melting point propylene resin (A′-1) and 50% by weight of the above low melting point propylene resin (A ″ -6) were combined. Using a resin composition (the ratio of 3MB-1 polymer was 0.0072% by weight in the resin composition, and granulation was performed in the same manner as in Example 1), a two-type two-layer (layer) with a total thickness of 1.2 mm A thickness ratio of the upper layer: lower layer = 1: 2) was formed. Further, in the same manner as in Example 1, a longitudinally uniaxially stretched sheet having a thickness of 0.3 mm was formed by roll stretching to obtain a thermoformed body of the sheet. Table 3 shows the measured physical properties of the obtained sheet and thermoformed body.

[Example 12]
The same procedure as in Example 11 was performed, except that the layer thickness ratio was changed to upper layer: lower layer = 1: 4 in Example 11, and the results are shown in Table 3.

[Example 13]
In Example 11, 5% by weight of the high melting point propylene resin (A′-1) used in Example 1 and 95% of the low melting point propylene resin (A ″ -6) were used for the upper layer (low melting point layer). Using a resin composition in combination with wt% (the proportion of 3MB-1 polymer was 0.0018 wt% in the resin composition, and granulation was performed in the same manner as in Example 1), the layer thickness ratio was the upper layer: Lower layer = 1: 1, except that the preheating roll temperature was changed to 130 ° C., the same operation as in Example 11 was carried out. The results are shown in Table 3.

[Example 14]
The resin composition used for the lower layer in Example 11 was subjected to longitudinal uniaxial stretching (single layer sheet) in the same manner as in Example 1, and the results are shown in Table 3.

[Comparative Example 6]
Table 3 shows the physical properties of the unstretched polypropylene (PP) sheet (thickness 0.3 mm) currently used in food container lids and the like.

[Comparative Example 7]
Table 3 shows the physical properties of the biaxially oriented polystyrene sheet (OPS sheet) (thickness 0.25 mm) that is currently used for lids for lunch boxes.

  The stretched sheet containing the propylene-based resin composition (A) for stretched sheets of the present invention has a very good balance of rigidity, heat-resistant rigidity, transparency, uniform stretchability, and thermoformability, and from this stretched sheet, The obtained thermoformed body has high rigidity, heat resistance rigidity, transparency, oil resistance, etc. and low specific gravity, so it can be widely used as packaging materials for food, medical instruments, pharmaceuticals, electronic parts, stationery, miscellaneous goods, etc. Can do.

Claims (8)

10 to 90% by weight of a high melting point propylene resin (A ′) having a melting point measured by DSC of 156 to 170 ° C.,
Including at least one low melting point propylene-based resin (A ″) having a melting point of 70 to 155 ° C. measured by DSC of 10 to 90% by weight (provided that A ′ and A ″ are 100% by weight in total) And
A propylene-based resin composition (A) for stretched sheets, which satisfies the following requirements [1] to [4].
[1] The melt flow rate (230 ° C., 2.16 kg load) is 0.5 to 10.0 g / 10 min.
[2] The melting point measured by DSC is 150 to 170 ° C.
[3] The α-olefin comonomer content is 1 to 11 mol% in the propylene-based resin composition (A) for stretched sheets.
[4] Includes nucleating components.   The α-olefin comonomer content of the high melting point propylene-based resin (A ′) is 0 to 1.5 mol%, and the α-olefin comonomer content of the low melting point propylene resin (A ″) is 1.6 to 24 mol%. The propylene-based resin composition (A) for stretched sheets according to claim 1, wherein the propylene-based resin composition (A) is for stretched sheets.   The single layer sheet (B1) which extended | stretched the propylene-type resin composition (A) for stretched sheets of Claim 1 or 2 at least to the uniaxial direction. A multilayer sheet (B2) using the propylene-based resin composition for stretched sheets (A) according to claim 1 or 2 in at least either the uppermost layer or the lowermost layer,
The multilayer sheet is at least uniaxially stretched, and
The melting point (Tm1) of the uppermost layer and the melting point (Tm2) of the lowermost layer of the multilayer sheet are
1 ≦ Tm2−Tm1 ≦ 100 (° C.)
Multilayer sheet (B2) characterized by satisfying the above relationship. A multilayer sheet (B2 ') using the propylene-based resin composition (A) for stretched sheets according to claim 1 or 2 as both an uppermost layer and a lowermost layer, wherein the outermost layer of the multilayer sheet (B2') Α-olefin comonomer content (C1) of the resin composition constituting the upper layer and α-olefin comonomer content (C2) of the resin composition constituting the lowermost layer,
C1> C2
A multilayer sheet (B2 ') characterized by satisfying the above relationship.   A thermoformed article obtained by thermoforming the single-layer sheet (B1) according to claim 3.   A thermoformed article obtained by thermoforming the multilayer sheet (B2) according to claim 4 or the multilayer sheet (B2 ') according to claim 5.   A thermoformed article used as a material for wrapping contents of food, medical instruments, pharmaceuticals, electronic parts, stationery, miscellaneous goods, etc., wherein the uppermost layer of the multilayer sheet (B2) or (B2 ′) is the contents The thermoformed body according to claim 7, wherein the thermoformed body is obtained by thermoforming so as to be on the outer surface side.