CN101855289A - Propylene resin composition for stretched sheet, stretched sheet containing same, and thermoformed article - Google Patents

Abstract

Disclosed are: a propylene resin composition for a stretched sheet having excellent stiffness, heat resistant stiffness, transparency, uniform stretchability and thermal moldability; and a stretched sheet and a thermally molded article, each of which comprises the resin composition. The propylene resin composition for a stretched sheet comprises 10 to 90 wt% of a high-melting-point propylene resin (A') having a melting point of 156 to 170 DEG C as measured by DSC and 10 to 90 wt% of at least one low-melting-point propylene resin (A'') having a melting point of 70 to 155 DEG C as measured by DSC (provided that the total amount of the components (A') and (A'') is defined as 100 wt%), and fulfils the following requirements [1] to [4]: [1] the propylene resin composition has a melt flow rate (230 DEG C, 2.16 kg load) of 0.5 to 10.0 g/10 min; [2] the propylene resin composition has a melting point of 150 to 170 DEG C as measured by DSC; [3] the propylene resin composition (A) contains an a-olefin comonomer at a content of 1 to 11 mol%; and [4] the propylene resin composition contains a nucleating agent.

Description

Propylene resin composition for stretched sheet, stretched sheet containing same, and thermoformed article

technical field

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

Background technique

Highly transparent sheets are widely used as packaging materials for food, medical equipment, pharmaceuticals, electronic components, stationery, miscellaneous goods, and the like. As raw materials, biaxially oriented polystyrene (OPS) sheets, polyvinyl chloride (PVC) sheets or amorphous polyterephthalene Ethylene glycol formate (A-PET) sheet, etc.

In recent years, from the viewpoints of environmental protection, heat-resistant rigidity, oil resistance, and low specific gravity, substitution to polypropylene sheets has been progressing.

Since polypropylene has crystallinity, it becomes a translucent sheet as it is. Therefore, a method of adding a nucleating agent is known as a general method for improving transparency and rigidity (for example, it is described in JP-A-2002-284942). However, since rigidity (normal temperature) and transparency are not sufficient also by the said method, the substitution to a polypropylene sheet is limited to some applications.

However, polypropylene is known to improve physical properties such as rigidity and transparency by stretching.

The stretching ratio of a biaxially stretched polypropylene film known as BOPP is usually high at a ratio of length×width=5×10 times. In order to obtain the sheet thickness (0.1 to 1 mm) that is the object of the present invention by such high-ratio stretching, the thickness of the sheet (roll film) before stretching must be 5 to 50 mm (BOPP is usually 1 to 3 mm) , If the roll film of such thickness is formed, it is difficult to form the roll film, and it cannot be stretched in existing equipment. In this way, when the roll film is made into a normal thickness and stretched at a low ratio, stretching unevenness (thickness unevenness) due to stretching residue (necking) tends to occur, so it is difficult to obtain the target sheet thickness.

In the case of uniaxial stretching, even if it can be stretched at a low ratio, the stretching unevenness is less than the above method, and it is easier to obtain the target sheet thickness. However, in terms of thermoformability, the stretching ratio must be controlled below 3 times. Therefore, sheet physical properties such as rigidity and transparency become insufficient (for example, JP-A-53-94371 and JP-A-53-128673). In addition, there is also known a method of uniaxial stretching in combination with a special web quenching method (for example, Japanese Patent Publication No. 63-16256 and Japanese Patent Publication No. 63-62377), but the physical properties of the sheet are slightly limited. The improvement is hardly sufficient, and it is not preferable because the cost of equipment (manufacturing cost) becomes high.

Patent Document 1: Japanese Patent Laid-Open No. 2002-284942

Patent Document 2: Japanese Patent Application Laid-Open No. 53-94371

Patent Document 3: Japanese Patent Laid-Open No. 53-128673

Patent Document 4: Japanese Patent Publication No. 63-16256

Patent Document 5: Japanese Patent Publication No. 63-62377

Contents of the invention

The present invention is made in order to solve the problems associated with the prior art as described above, and provides a stretching method that is not restricted by uniaxial stretching, biaxial stretching, roll film cooling, and stretching ratio, and has A propylene-based resin composition for a stretched sheet excellent in rigidity, heat-resistant rigidity, transparency, uniform stretchability, and thermoformability, and a stretched sheet and a thermoformed article containing the resin composition.

The inventors of the present invention conducted intensive studies to solve the above-mentioned problems, and as a result, found that a resin composition in which propylene-based resins having a melting point in a specific range are combined and has a wide composition distribution can be stretched without being restricted by a stretching method, Furthermore, the stretched sheet containing this resin composition has an extremely good balance of rigidity, heat-resistant rigidity, transparency, uniform stretchability, and thermoformability, and thus completed the present invention.

That is, the present invention is specified by the matters described below.

(1) A propylene-based resin composition (A) for a stretched sheet, comprising: 10-90% by weight of a high-melting-point propylene-based resin (A') with a melting point of 156-170°C measured by DSC; and at least one 10 to 90% by weight of one or more kinds of low-melting propylene-based resins (A″) having a melting point of 70 to 155°C as measured by DSC, wherein the total of A′ and A″ is 100% by weight,

And, the propylene-based resin composition (A) for a stretched sheet satisfies the following conditions [1] to [4]:

[1] MFR (230°C, 2.16kg load) is 0.5～10.0g/10min;

[2] The melting point measured by DSC is 150-170°C;

[3] In the propylene-based resin composition (A) for stretched sheets, the α-olefin comonomer content is 1 to 11 mol%;

[4] Contains nucleating components.

(2) The propylene-based resin composition (A) for stretched sheets as described in (1), wherein the α-olefin comonomer content of the high-melting-point propylene-based resin (A') is 0 to 1.5 mol%, and the low-melting-point propylene-based resin (A') The α-olefin comonomer content of the propylene-based resin (A") is 1.6 to 24 mol%.

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

(4) A multilayer sheet (B2), which uses the propylene-based resin composition (A) for stretched sheets described in (1) or (2) at least in any one of the uppermost layer or the lowermost layer, the The multilayer sheet is stretched at least in a uniaxial direction, and the melting point (Tm1) of the uppermost layer and the melting point (Tm2) of the lowermost layer of the multilayer sheet satisfy the relationship of 1≤Tm2-Tm1≤100 (°C).

(5) A multilayer sheet (B2'), which uses the propylene resin composition (A) for a stretched sheet described in (1) or (2) in the two layers of the uppermost layer and the lowermost layer to form a multilayer sheet. The α-olefin comonomer content (C1) of the resin composition of the uppermost layer of the layer sheet (B2') and the α-olefin comonomer content (C2) of the resin composition constituting the lowermost layer satisfy the relationship of C1>C2.

(6) A thermoformed body obtained by thermoforming the single-layer sheet (B1) described in (3).

(7) A thermoformed article obtained by thermoforming the multilayer sheet (B2) described in (4) or the multilayer sheet (B2') described in (5).

(8) The thermoformed body as described in (7), which is used as a material for packaging food, medical equipment, pharmaceuticals, electronic components, stationery, groceries, etc., and the thermoformed body is made of the above-mentioned multilayer sheet (B2) Or (B2') obtained by thermoforming so that the uppermost layer becomes the outer side with respect to the said content.

Invention effect

Single-layer and multi-layer stretched sheets comprising the propylene-based resin composition (A) for stretched sheets of the present invention have an extremely good balance of rigidity, heat-resistant rigidity, transparency, uniform stretchability, and thermoformability . Furthermore, thermoformed articles obtained from the single-layer and multi-layer stretched sheets are characterized by high rigidity, heat-resistant rigidity, transparency, oil resistance, etc., and low specific gravity. In addition, the thermoformed body obtained from the multilayer stretched sheet has excellent shape stability due to less post-shrinkage after molding and less deformation. Therefore, single-layer and multi-layer stretched sheets containing the propylene-based resin composition (A) for stretched sheets of the present invention can be used as packaging materials for food, medical equipment, pharmaceuticals, electronic parts, stationery, miscellaneous goods, etc. widely used.

Detailed ways

The propylene-based resin composition (A) for stretched sheets of the present invention contains a high-melting-point propylene-based resin (A') and at least one or more low-melting-point propylene-based resins (A").

High melting point propylene resin (A')

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

The high melting point propylene resin (A') is a polymer containing propylene as a structural unit, a homopolymer of propylene, or propylene and ethylene or an α-olefin with 4 to 20 carbon atoms (α-olefin comonomer) random copolymers. Here, examples of α-olefins 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, etc. Among them, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable. The content of the α-olefin comonomer in the high melting point propylene resin (A') is 0 to 1.5 mol%, preferably 0 to 1.2 mol%, more preferably 0 to 0.6 mol%.

In addition, a preferred aspect of the high melting point propylene resin (A') is that the melt flow rate (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. within 10 minutes. When MFR is in this range, the extrudability of a roll film will be excellent.

In addition, a preferred embodiment of the high melting point propylene resin (A') is the stereoregularity index [M ₅ ] obtained from the absorption intensity of Pmmmm and Pw in the ¹³ C-NMR spectrum by the following formula (Eq-1): The value of is in the range of 0.960 to 0.990, more preferably in the range of 0.970 to 0.990. When the stereoregularity index [M ₅ ] is within this range, the stretched sheet is excellent in rigidity and heat-resistant rigidity.

$<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Pmmmm</span>}<span\; class="notranslate">\; ]</span>}{<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Pw</span>}<span\; class="notranslate">\; ]</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Eq</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

(In the formula, [Pmmmm] represents the absorption intensity derived from the methyl group of the third unit in the site where five propylene units are continuously and isotactically bonded, and [Pw] represents the absorption intensity derived from the methyl group of the propylene unit.)

The method for producing such a high melting point propylene resin (A') can be, for example, the methods described in JP-A-2-84404, JP-A-2-229807, JP-A-3-7703, etc. .

Low Melting Point Propylene Resin (A″)

The Tm of the low-melting propylene resin (A") is in the range of 70 to 155°C, preferably in the range of 70 to 150°C, more preferably in the range of 78 to 148°C. If the Tm is in this range, it contains The stretched sheet of the propylene resin composition (A) of the present invention is excellent in transparency, uniform stretchability, and thermoformability.

The low-melting propylene resin (A") is a polymer containing propylene as a structural unit, and is a random copolymer of propylene and ethylene or an α-olefin (α-olefin comonomer) with 4 to 20 carbon atoms. In Here, examples of α-olefins 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, etc. Among them, ethylene or carbon atoms of 4 to 10. α-olefin. The content of the α-olefin comonomer in the low-melting propylene resin (A") is 1.6 to 24 mol%, preferably 3.0 to 24 mol%, more preferably 3.7 to 24 mol%.

In addition, a preferred aspect of the low-melting propylene resin (A") is that MFR (230°C, 2.16 kg load) is preferably in the range of 0.3 to 15.0 g/10 min, more preferably in the range of 0.6 to 9.0 g/10 min. When MFR is in this range, the extrudability of a roll film will be excellent.

As a method for producing such a low-melting propylene resin (A"), if the Tm is 130°C or higher, the above-mentioned method for producing the high-melting propylene resin (A') can be used, but when the Tm is lower than 130°C, due to The production amount of isotactic polypropylene increases, so it cannot be used. In contrast, the method using a metallocene catalyst can suppress the production amount of isotactic polypropylene, so it is particularly preferable as a production method of a low-melting point propylene resin (A") , for example, can be used as described in WO01/027124 communique, Japanese patent publication No. 2002-275282 communique, Japanese patent publication No. Methods.

Propylene resin composition for stretched sheet (A)

The propylene-based resin composition (A) for stretched sheets of the present invention is a resin composition obtained by combining a high-melting-point propylene-based resin (A') and at least one low-melting-point propylene-based resin (A"). Resin The composition ratio of the composition (A) is that in the resin composition (A), the high melting point propylene resin (A') is 10 to 90% by weight, preferably 20 to 80% by weight; at least one or more low melting point propylene Resins (A") (the total amount of resins (A") when there are two or more types) are 10 to 90% by weight, preferably 20 to 80% by weight.

The propylene-based resin composition (A) for stretched sheets of the present invention has MFR (230°C, 2.16 kg load) in the range of 0.5 to 10.0 g/10 min, preferably 1.0 to 5.0 g/10 min, and Tm In the range of 150-170°C, preferably in the range of 155-170°C, more preferably in the range of 158-170°C, in the resin composition (A), the content of α-olefin comonomer is 1.0- It is in the range of 11 mol%, preferably in the range of 1.5 to 8 mol%, and contains 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 two or more stages of polymerization tanks connected in series, the high melting point propylene resin (A') can be produced in the front stage and the low melting point propylene resin (A") can be continuously produced in the rear stage.

In addition, the high melting point propylene-based resin (A') and the low melting point propylene-based resin produced separately are melt-kneaded using a single-screw extruder, a multi-screw extruder, a kneader, a Banbury mixer, etc. (A"), the propylene-based resin composition (A) can also be obtained, and the said resin can also be directly supplied to a sheet forming machine.

Nucleating component

As the nucleating component contained in the propylene resin composition (A) for stretched sheets of this invention, a well-known nucleating agent can be used without limitation. For example, sorbitol compounds, phosphoric acid ester compounds, aliphatic dicarboxylic acids with 4 to 12 carbon atoms and their metal salts, aromatic carboxylic acids and their metal salts, rosin acid metal salts and silicon Magnesium acid (talc), etc. In addition, after prepolymerizing the reactive monomer as a nucleating component in a polypropylene polymerization catalyst, propylene is polymerized, and the resulting polypropylene (polymer nucleating agent) is also included in the nucleating component. Among these nucleating components, the above-mentioned polymer nucleating agent is preferable because it has high compatibility and nucleating effect, and has very little contamination to sheet forming machines and thermoforming machines.

Examples of reactive monomers used in the prepolymerization of the above-mentioned polymer nucleating agent include 3-methyl-1-butene, 3-methyl-1-pentene, and 4-methyl-1-pentene , 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethane Dimethyl-1-hexene, allylnaphthalene, allylnorbornene, styrene, dimethylstyrenes, vinylnaphthalene, allyltoluene, allylbenzene, vinylcyclohexane , Vinyl cyclopentane, vinyl cycloheptane, allyl trialkylsilanes, etc.

As the method for producing the above-mentioned 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 0.001-0.5 weight part with respect to 100 weight part of propylene-type resin compositions (A) for stretched sheets, Preferably they are 0.0018-0.3 weight part.

additive

When forming a stretched sheet from the propylene-based resin composition (A) for a stretched sheet of the present invention as a raw material, antioxidants, light-resistant stabilizers, and ultraviolet absorbers may be added within the range not exceeding the purpose of the present invention. , metal soap, hydrochloric acid absorbent, lubricant, antistatic agent, antifogging agent and antiblocking agent and other additives.

The addition amount of these additives varies depending on the type, but as long as it is within the range that does not impair the object of the present invention, it is usually 3 parts by weight or less with respect to 100 parts by weight of the propylene-based resin composition for stretched sheet (A). .

Stretched Sheets and Thermoforms

Balance of rigidity, heat-resistant rigidity, transparency, uniform stretchability, and thermoformability of a sheet stretched at least in a uniaxial direction containing the propylene-based resin composition (A) for a stretched sheet of the present invention extremely good.

The stretched sheet of the present invention can be obtained by a known production method. For example, the above-mentioned propylene-based resin composition (A) for a stretched sheet (A) is supplied to an extruder (multiple extruders are used for multilayering), and the The temperature of the resin is adjusted to 190-280°C, and it is extruded from the T-die installed at the front of the extruder (for multi-layers, it is just before reaching the T-die or after it is merged in the T-die), and the utilization is adjusted to 20-20°C. The cooling roll at a temperature of 80°C stretches and coils to form a roll film. Reheat in a preheating roll adjusted to a temperature of 130-160°C, roll stretching in the longitudinal direction at a stretching ratio of 2 to 5 times, and relax 0-10 by annealing rolls adjusted to a temperature of 100-160°C. % obtained by edge coiling.

In addition, the stretching method is not limited. In addition to the above-mentioned longitudinal uniaxial stretching, transverse uniaxial stretching using a tenter to stretch in the transverse direction may be used, or stretching may be performed after the above-mentioned longitudinal uniaxial stretching. Sequential biaxial stretching in which the tenter is stretched in the transverse direction, or simultaneous biaxial stretching in which only the tenter is stretched in the longitudinal and transverse directions.

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

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

In general, a stretched polypropylene sheet has a characteristic that molecular chains stretched by stretching are relaxed by heat and thus shrink. Since the glass transition temperature (Tg) of polypropylene is 0° C. or lower, it gradually shrinks (post-shrinks) even at normal temperature. The thermoformed body obtained by secondary processing of polypropylene stretched sheet by thermoforming such as hot plate forming and vacuum compression forming may shrink and deform after storage in summer (high temperature) and long-term storage (containers, etc. have In the case of a square shape, the edge of the thermoformed body tends to be warped outward from the original state and deformed). Since the same applies to the thermoformed body formed from the single-layer sheet (B1) of the present invention, the shape, storage method, etc. of the thermoformed body are restricted to some extent.

On the other hand, the thermoformed body formed from the multilayer sheet (B2) of the present invention has extremely small deformation as described above, and therefore, restrictions on shape, storage method, etc. can be eliminated or relaxed.

In the multilayer sheet (B2) of the present invention, the propylene-based resin composition (A) for stretched sheets of the present invention is used at least in either the uppermost layer or the lowermost layer, and in the uppermost layer, a propylene resin composition having a melting point lower than the lowest As the polypropylene of the lower layer, it is preferable to use the propylene-based resin composition (A) for stretched sheets. In this case, the melting point difference (ΔTm) between the uppermost layer and the lowermost layer (two outermost layers) is 1 to 100°C, preferably 3 to 30°C, more preferably 3 to 15°C. That is, it is important to design the layer structure so that the melting point (Tm1) of the uppermost layer of the multilayer sheet and the melting point (Tm2) of the lowermost layer satisfy the relationship of (I), preferably satisfy the relationship of (II), more preferably satisfy the relationship of (III) )Relationship.

(I) 1≤Tm2-Tm1≤100(°C)

(II) 3≤Tm2-Tm1≤30(°C)

(III) 3≤Tm2-Tm1≤15(°C)

In addition, in the multilayer sheet (B2') of the present invention, the propylene-based resin composition (A) for stretched sheets of the present invention is used in the two layers of the uppermost layer and the lowermost layer, and it is important that the resin constituting the uppermost layer The α-olefin comonomer content (C1) of the composition and the α-olefin comonomer content (C2) of the resin composition constituting the lowermost layer satisfy the relationship of C1>C2.

In addition, when thermoforming the multilayer sheet, the direction of the sheet is aligned so that the above-mentioned uppermost layer (low Tm) is the outer side of the thermoformed body, and the above-mentioned lowermost layer (high Tm) is the inner surface side, thereby suppressing Deformation resulting from post-shrinkage.

That is, when thermoforming the multilayer sheet of the present invention having the above-mentioned structure, the orientation of the sheet is aligned so that the uppermost layer (low Tm side) of the multilayer sheet (B2) or (B2') ) is the outer side with respect to the content, the lowermost layer (high Tm side) of the multilayer sheet (B2) or (B2') is the inner side with respect to the content, and, according to other expressions, the multilayer sheet (B2 ) or (B2'), the uppermost layer (low Tm side) is on the outer side of the convex surface of the thermoformed body, and the lowermost layer (high Tm side) is on the inner concave surface, so that deformation caused by post-shrinkage can be suppressed.

In addition, when thermoforming the multilayer sheet (B2') of the present invention having the above-mentioned structure, the orientation of the sheet is aligned so that the uppermost layer (C1 side) of the multilayer sheet (B2') The outermost layer (C2 side) is on the inner side with respect to the contents, and the uppermost layer (C1 side) of the multilayer sheet (B2') is in the shape of the thermoformed body according to other expressions. The outer side of the convex surface and the lowermost layer (C2 side) are on the inner side of the concave surface, so that deformation due to post-shrinkage can also be suppressed.

Usually, polypropylene is stretched at a temperature ranging from the crystallization temperature (Tc) to Tm. The aftershrinkage of the stretched sheet depends on its stretching temperature, indicating that the lower the stretching temperature (closer to Tc), the greater the aftershrinkage, and the higher the stretching temperature (closer to Tm), the smaller the aftershrinkage Propensity. Therefore, the thermoformed body formed from the above-mentioned multilayer sheet (B2) has the above-mentioned uppermost layer (low Tm) on the outer side of the thermoformed body and the aforementioned lowermost layer (high Tm) on the inner side. The side is stretched at a temperature closer to Tm than the inner side, and the aftershrinkage of the outer side of the thermoformed body is smaller than that of the inner side, so the deformation becomes extremely small. In addition, by adjusting the melting point difference (ΔTm), layer thickness ratio, stretching temperature, etc. of the multilayer sheet, the amount of post-shrinkage of the inner and outer surfaces can be arbitrarily controlled, so it can be used in various shapes.

The multilayer sheet (B2) of the present invention can obtain more added value by combining other resins in the intermediate layer within the range not exceeding the purpose of the present invention. For example, oxygen and carbon dioxide barrier properties are improved by using an ethylene-vinyl alcohol copolymer in the intermediate layer, water vapor barrier properties are improved by using a polypropylene resin composition containing a hydrogenated petroleum resin in the intermediate layer, and the like. In addition, examples of other resins that can be used in the intermediate layer include polyamide resins such as polyvinyl alcohol resins, polyvinylidene chloride resins, polyacrylonitrile resins, m-xylylenediamine 6, and nylon 6, Polyester resins such as polyethylene terephthalate and polybutylene terephthalate.

In addition, the thermoformed body obtained from the stretched sheet of the present invention has high rigidity, heat-resistant rigidity, transparency, oil resistance, etc., and low specific gravity, so it can be used as a food, medical equipment, pharmaceuticals, electronic components, stationery, etc. , groceries and other packaging materials are widely used.

[Example]

Next, the present invention will be described in detail based on examples, but the present invention is not limited by these examples.

The physical property measurement methods in the examples are as follows.

1) Melt flow rate (MFR[g/10min])

According to ASTM D-1238, it is measured at a temperature of 230°C and a load of 2.16kg. Nitrogen gas is not particularly introduced into the barrel, and the pellets are directly put into the barrel to melt them.

2) Melting point (Tm[°C])

In DSC, heat up from 30°C to 230°C at 10°C/min, keep at 230°C for 10 minutes, cool down to 30°C at 10°C/min, and then raise the temperature at 10°C/min to eliminate the endothermic The peak temperature was taken as the melting point.

3) Fraction of isotactic pentads (mmmm: [M ₅ ])

It is determined by the above formula (Eq-1) from the absorption intensity of Pmmmm and Pw in the ¹³ C-NMR spectrum. Among them, the peak assignment was performed according to Polymer, 1993, Vol34, No14, 3129-3131.

4) Uniform stretchability (uneven thickness [-])

The thickness of the stretched sheet was measured 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 of elasticity (MPa)

The ASTM D-638 type 4 test piece was punched out from the sheet, the distance between the chucks was 46mm, the speed was 50mm/min, the temperature was 23°C or 110°C, and the initial inclination of the stress-distortion curve during stretching was used. Find out the degree.

6) Haze (HAZE[%])

Measurement was performed using a TURBIDIMETER produced by Nippon Denshoku Industries using an integrating sphere of 150Φ in accordance with JIS K7361.

7) Heat shrinkage (SH[%])

A test piece with a width of 10 mm and a length of 100 mm (L0) was punched out from the sheet, heated in an air oven at 130° C. for 15 minutes, and the length (L1) after heating was measured and calculated by the following formula (Eq-2).

$\mathrm{<span\; class="notranslate">\; SH</span>}<span\; class="notranslate">\; [</span><span\; class="notranslate">\; \%</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Eq</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

8) Thermoformability (formation score [points])

In the hot plate forming machine, use the container model mold (size: □90mm, depth: 20mm) to perform thermoforming under the prescribed molding conditions, and visually observe the shape of the thermoformed body, and evaluate it on a scale of 5 points (the greater the value, the thermoforming The better the performance, the better the score is 3 points or more).

9) Deformation of thermoformed body (warping deformation [mm])

The thermoformed body was aged in an air oven at 50° C. for 1 day, and the amount of edge warpage of the thermoformed body was measured.

10) specific gravity

Measured using the water displacement method according to JIS K7112.

[Example 1]

After prepolymerizing 3-methyl-1-butene (3MB-1) as a nucleating component, 0.1 parts by weight of tetrakis[methylene-3-( 3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane (IRGANOX1010, manufactured by Ciba Specialty Chemicals, trademark) and 0.1 parts by weight of tris(2,4-di-tert-butylphenol) phosphate (IRGAFOS168, produced by Ciba Specialty Chemicals, trademark), as a neutralizing agent, mixed with 0.1 parts by weight of calcium stearate (produced by Nippon Oils and Fats Co., Ltd.), using a single-screw extruder, melting and kneading with a resin temperature of 230° C. to produce Granules become granular. Wherein, the resin composition is obtained by 75% by weight of high melting point propylene resin (A′-1) obtained by homopolymerization of propylene with Tm=167°C, MFR=2g/10min, mmmm=0.972, and 6mol% of propylene and ethylene by copolymerization Tm = 135 ° C, MFR = 2g/10min low melting point propylene resin (A"-1) 25% by weight combined. At this time, the ratio of the 3MB-1 polymer as a nucleating component is equal to the above resin combination It was 0.027% by weight in the compound.Tables 1 and 2 show the physical properties of the obtained resin composition (pellets).

The above-mentioned pellets were supplied to a longitudinal uniaxially stretched sheet forming machine, extruded from a T-shaped die at a resin temperature of 250° C., and formed into a roll film with a thickness of 1.2 mm while stretching and winding with a cooling roll at a temperature of 30° C. After reheating the preheated roll at a temperature of 150° C., roll stretching was carried out at a draw ratio of 4 times, and annealed at a temperature of 110° C. to obtain a longitudinally uniaxially stretched sheet with a thickness of 0.3 mm. Tables 1 and 2 show the physical properties of the obtained sheets.

In the hot plate forming machine, use the above-mentioned container model mold, set the compressed air pressure to 0.64MPa, the degree of vacuum to 0.09MPa, the heating time of the sheet to be 3s, and the forming time to be 3s, and heat the stretched sheet to Thermoforming was performed at a plate temperature in the range of 100 to 160°C. Tables 1 and 2 show the best molding scores without cloudiness in the obtained thermoformed products.

[Example 2]

In addition to using a resin combination in which 50% by weight of the high-melting propylene-based resin (A'-1) used in Example 1 and 50% by weight of the low-melting propylene-based resin (A"-1) used in Example 1 were used Table 1 shows the results in the same manner as in Example 1 except that the ratio of the 3MB-1 polymer was 0.018% by weight in the resin composition.

[Example 3]

After pre-polymerization of 3-methyl-1-butene as a nucleating component, a high-melting propylene-based resin (A'- 2) A resin composition obtained by combining 50% by weight and 50% by weight of the low-melting propylene resin (A″-1) used in Example 1 (the ratio of the 3MB-1 polymer in the resin composition is 0.017% by weight ) except that it was carried out in the same manner as in Example 1, and the results are shown in Table 1.

[Example 4]

In addition to using 50% by weight of the high melting point propylene resin (A'-2) used in Example 3, 6 mol% of propylene and ethylene obtained by copolymerization of Tm = 135 ° C, MFR = 10g/10min low melting point propylene resin (A " -2) Except the resin composition which combined 50 weight% (the ratio of 3MB-1 polymer is 0.017 weight% in a resin composition), it carried out similarly to Example 1, and Table 1 shows the result.

[Example 5]

In addition to using 50% by weight of the high-melting point propylene-based resin (A'-1) used in Example 1, and 5.4 mol% of propylene and ethylene copolymerized with a low-melting point propylene-based resin with Tm=140°C and MFR=0.5g/10min (A″-3) 50% by weight of the combined resin composition (the ratio of the 3MB-1 polymer in the resin composition was 0.018% by weight), and the results were shown in Table 1 in the same manner as in Example 1. .

[Example 6]

In addition to using 40% by weight of high-melting propylene-based resin (A'-3) obtained by homopolymerization of propylene with Tm = 165°C, MFR = 0.5g/10min, mmmm = 0.979, the low-melting propylene-based resin used in Example 5 (A″-3) 50% by weight and 10% by weight of the propylene resin (A'-1) used in Example 1 as a nucleating component Table 1 shows the results in the same manner as in Example 1 except that it was 0.0036% by weight in the composition.

[Example 7]

Relative to containing 25% by weight of the high melting point propylene resin (A'-1) used in Example 1, the low melting point propylene resin ( A "-4) 50% by weight, and propylene and 23.5mol% 1-butene copolymerized to obtain Tm = 78 ° C, MFR = 7g/10min ultra-low melting point propylene resin (A "-5) 25% by weight resin 100 parts by weight of the composition, combined with bis[2,4,8,10-tetra-tert-butyl-6-hydroxyl-12H-dibenzo[d,g][1,3,2]di 0.13 parts by weight of oxaphosphacycline-6-oxide] aluminum hydroxide salt (NA-21, manufactured by ADEKA Corporation, trademark) was used to obtain a resin composition. Except having used this resin composition, it melt-kneaded similarly to Example 1, and granulated into pellet form (the ratio of the 3MB-1 polymer is 0.009 weight% in a resin composition). In addition, the above-mentioned pellets were supplied to a sheet forming machine, and molded into a stretched sheet in the same manner as in Example 1 except that the temperature of the preheating roll was changed to 130°C. Table 1 shows the results.

[Comparative example 1]

In addition to removing the low-melting point propylene-based resin (A″-1) from the resin composition used in Example 1, only the high-melting point propylene-based resin (A′-1) was used as 100% by weight (3MB-1 polymer The results were shown in Table 1 in the same manner as in Example 1 except that the ratio was 0.036% by weight in the resin.

[Comparative example 2]

In addition to removing the nucleating component (A'-1) from the resin composition used in Example 6, a 50% by weight high-melting point propylene-based resin (A'-3) and a low-melting point propylene-based resin (A"- 3) Except the resin composition which combined 50 weight%, it carried out similarly to Example 1, and Table 1 shows the result.

[Comparative example 3]

In addition to removing the high-melting propylene-based resin (A'-1) and the ultra-low-melting propylene-based resin (A"-5) from the resin composition used in Example 7, forming only the low-melting propylene-based resin (A"-5) -4) Except the resin composition which combined 100 weight% and 0.13 weight part of nucleating agents (NA-21), it carried out similarly to Example 7, and Table 1 shows the result.

[Comparative example 4]

Except for using a resin composition composed of 50% by weight of the propylene-based resin (A′-1) used in Example 1 and 50% by weight of the ultra-low melting point propylene-based resin (A″-5) used in Example 7 (the ratio of the 3MB-1 polymer is 0.018% by weight in the resin composition), it carried out similarly to Example 7, and Table 1 shows the result.

[Example 8]

The pellets obtained in Example 1 were supplied to a sequential biaxial stretching sheet forming machine, extruded from a T-shaped die at a resin temperature of 250°C, and formed into a roll with a thickness of 1.8 mm while stretching and coiling with a cooling roll at a temperature of 30°C. The tube film is reheated with a preheating roll at a temperature of 150°C, stretched at a draw ratio of 3 times, and then supplied to a tenter, and stretched transversely at a stretch temperature of 155°C and a draw ratio of 3 times. Annealing was performed while relaxing the width by 5% at a temperature of 160° C. to obtain a sequentially biaxially stretched sheet having a thickness of 0.2 mm. Table 2 shows the physical properties of the obtained sheet.

[Example 9]

Table 2 shows the results in the same manner as in Example 8, except that it was formed into a roll film having a thickness of 3.0 mm in Example 8 and the transverse stretching was changed to 5 times.

[Example 10]

Cut the roll film with a thickness of 1.8mm obtained in Example 8 into a size of □85mm, and on a bench-type biaxial stretching machine, the stretching temperature is 155°C and the stretching ratio is longitudinal × transverse = 3 × 3 After performing simultaneous biaxial stretching two times, annealing was performed while relaxing 5% of the width at a temperature of 160° C. to obtain a simultaneously biaxially stretched sheet having a thickness of 0.2 mm. Table 2 shows the physical properties of the obtained sheet.

[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 stretched and taken up by a cooling roll at a temperature of 30°C to obtain an unstretched sheet with a thickness of 0.3 mm. Table 2 shows the physical properties of the obtained sheet.

[Table 2]

[Example 11]

Using a multilayer sheet molding machine with two series of extruders, 20% by weight of the high melting point propylene resin (A'-1) used in Example 1, and propylene and ethylene were used in the upper layer (low melting point layer). 6mol% copolymerization, and blended with 0.03 parts by weight of talc Tm = 139 ° C, MFR = 3g/10min low melting point propylene resin (A'-6) 80% by weight combined resin composition (granulation and embodiment 1), the lower layer uses a resin composition (3MB- 1 The ratio of the polymer is 0.0072% by weight in the resin composition, and the granulation is carried out in the same manner as in Example 1), and it is molded into two kinds of two-layer (layer thickness ratio is upper layer: lower layer=1: 2) of total thickness 1.2mm Roll film.The same as embodiment 1, be the longitudinal uniaxially stretched sheet material of thickness 0.3mm with roll stretch molding again, obtain the thermoformed body of this sheet material.Represent in table 3 the sheet material that obtains and heat Physical properties of molded products.

[Example 12]

In Example 11, except having changed the layer thickness ratio into upper layer: lower layer=1:4, it carried out similarly to Example 11, and Table 3 shows the result.

[Example 13]

Except that in Example 11, 5% by weight of the high melting point propylene-based resin (A'-1) and 95% by weight of the low melting point propylene-based resin (A"-6) used in Example 1 were used in the upper layer (low melting point layer). The combined resin composition (the ratio of the 3MB-1 polymer in the resin composition is 0.0018% by weight, and the granulation is carried out in the same manner as in Example 1), the layer thickness ratio is changed to upper layer: lower layer = 1: 1, pre- Except that the heat roll temperature was 130° C., the same procedure as in Example 11 was carried out, and the results are shown in Table 3.

[Example 14]

The resin composition used in the lower layer in Example 11 was uniaxially stretched in the longitudinal direction (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 an unstretched polypropylene (PP) sheet (thickness 0.3 mm) currently used as a lid material for a food container and the like.

[Comparative Example 7]

Table 3 shows the physical properties of a biaxially stretched polystyrene sheet (OPS sheet) (thickness 0.25 mm) currently used as a lid material for a lunch container, and the like.

[table 3]

Industrial availability

The stretched sheet containing the propylene-based resin composition (A) for stretched sheet of the present invention has an extremely good balance of rigidity, heat-resistant rigidity, transparency, uniform stretchability, and thermoformability. Thermoformed products obtained from sheets have high rigidity, heat-resistant rigidity, transparency, oil resistance, etc., and low specific gravity, so they can be widely used as packaging materials for food, medical equipment, pharmaceuticals, electronic components, stationery, and miscellaneous goods.

Claims (8)

1. A propylene-based resin composition (A) for a stretched sheet, characterized in that, Containing: 10% to 90% by weight of a high melting point propylene-based resin (A′) with a melting point of 156°C to 170°C measured by DSC; and 10-90% by weight of at least one low-melting propylene-based resin (A") with a melting point of 70-155°C measured by DSC, Here, the total of A' and A" is 100% by weight, The propylene resin composition (A) for a stretched sheet satisfies the following conditions [1] to [4]: [1] The melt flow rate (230°C, 2.16kg load) is 0.5～10.0g/10min; [2] The melting point measured by DSC is 150-170°C; [3] In the propylene-based resin composition (A) for stretched sheets, the α-olefin comonomer content is 1 to 11 mol%; [4] Contains nucleating components. 2. propylene-based resin composition (A) for stretched sheet as claimed in claim 1, is characterized in that: The α-olefin comonomer content of the high melting point propylene 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 % . 3. A single-layer sheet (B1), characterized in that: Stretching the propylene-based resin composition (A) for a stretched sheet according to claim 1 or 2 at least in a uniaxial direction. 4. A multilayer sheet (B2), characterized in that: Use the propylene-based resin composition (A) for a stretched sheet according to claim 1 or 2 at least in any one of the uppermost layer or the lowermost layer, The multilayer sheet is stretched in at least a uniaxial direction, and, The melting point (Tm1) of the uppermost layer and the melting point (Tm2) of the lowermost layer of the multilayer sheet satisfy the relationship of 1≤Tm2-Tm1≤100 (°C). 5. A multilayer sheet (B2'), characterized in that: The propylene-based resin composition (A) for stretched sheets according to claim 1 or 2 is used in the two layers of the uppermost layer and the lowermost layer, and The α-olefin comonomer content (C1) of the resin composition constituting the uppermost layer of the multilayer sheet (B2′) and the α-olefin comonomer content (C2) of the resin composition constituting the lowermost layer satisfy C1> C2 relationship. 6. A thermoformed body, characterized in that: Obtained by thermoforming the single-layer sheet (B1) according to claim 3. 7. A thermoformed body, characterized in that: Obtained by thermoforming the multilayer sheet (B2) according to claim 4 or the multilayer sheet (B2') according to claim 5. 8. The thermoformed body according to claim 7, characterized in that: Used as a material for packaging the contents of food, medical equipment, pharmaceuticals, electronic components, stationery, miscellaneous goods, etc., and This thermoformed body is obtained by thermoforming such that the uppermost layer of the multilayer sheet (B2) or (B2') becomes the outer side with respect to the content.